Quoting fsmithred (fsmithred@???):

> Oh, you must have missed my last report. Surely, you would agree that
> executing an executable file is doing something.

No, I didn't miss that. libsystemd0 didn't do anything, by your own
account. By said account, some piece of GNOME infrastructure took some
action ('removable drives no longer appear on the desktop').

I'm not surprised. GNOME is brittle, and a dependency hairball (as is
XFCE, because of core components in common with GNOME). My opinion,
yours under royalty-free licensing if you want it. ;->


You refer to '/lib/systemd/systemd-udevd' as 'an executable binary file
that libsystemd0 provides'. This appears to be the cause of the
confusion. That is _not_ a part of package libsystemd0.
https://packages.debian.org/stable/amd64/libsystemd0/filelist provides the list
(for the x86_64 package in current Debian-stable, as an example),
comprising one dynamic library, one symlink to that library, and two
small documentation files:

/lib/x86_64-linux-gnu/libsystemd.so.0
/lib/x86_64-linux-gnu/libsystemd.so.0.3.1
/usr/share/doc/libsystemd0/changelog.Debian.gz
/usr/share/doc/libsystemd0/copyright

Normally, when I say 'libsystemd0', I assume people mean
lib/x86_64-linux-gnu/libsystemd.so.0 (the symlink) or the binary it
points to, currently /lib/x86_64-linux-gnu/libsystemd.so.0.3.1 . But
even taking the most expansive possible interpretation of what you meant
when you said 'an executable binary file that libsystemd0 provides',
that does _not_ include systemd-udevd, which is simply not in that
package at all.

As you will see in
https://packages.debian.org/stable/amd64/udev/filelist, that executable
is in package udev, not package libsystemd0.



> For the past two years, people have been saying that libsystemd0 is just a
> library....

It's just a library. But check the list of files for yourself. Certainly
don't take my word for it.


> To summarize: libsystemd0 runs its program(s) even when systemd is not
> installed.

To summarise: You made a mistake.